rtsol.c revision 222732 
1/*	$KAME: rtsol.c,v 1.27 2003/10/05 00:09:36 itojun Exp $	*/
2
3/*
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Copyright (C) 2011 Hiroki Sato
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD: head/usr.sbin/rtsold/rtsol.c 222732 2011-06-06 03:06:43Z hrs $
33 */
34
35#include <sys/param.h>
36#include <sys/socket.h>
37#include <sys/uio.h>
38#include <sys/time.h>
39#include <sys/queue.h>
40#include <sys/wait.h>
41#include <sys/stat.h>
42
43#include <net/if.h>
44#include <net/route.h>
45#include <net/if_dl.h>
46
47#define	__BSD_VISIBLE	1	/* IN6ADDR_LINKLOCAL_ALLROUTERS_INIT */
48#include <netinet/in.h>
49#undef 	__BSD_VISIBLE
50#include <netinet/ip6.h>
51#include <netinet6/ip6_var.h>
52#include <netinet/icmp6.h>
53
54#include <arpa/inet.h>
55
56#include <netdb.h>
57#include <time.h>
58#include <fcntl.h>
59#include <unistd.h>
60#include <stdio.h>
61#include <err.h>
62#include <errno.h>
63#include <string.h>
64#include <stdlib.h>
65#include <syslog.h>
66#include "rtsold.h"
67
68static struct msghdr rcvmhdr;
69static struct msghdr sndmhdr;
70static struct iovec rcviov[2];
71static struct iovec sndiov[2];
72static struct sockaddr_in6 from;
73static int rcvcmsglen;
74
75int rssock;
76struct ifinfo_head_t ifinfo_head =
77	TAILQ_HEAD_INITIALIZER(ifinfo_head);
78
79static const struct sockaddr_in6 sin6_allrouters = {
80	.sin6_len =	sizeof(sin6_allrouters),
81	.sin6_family =	AF_INET6,
82	.sin6_addr =	IN6ADDR_LINKLOCAL_ALLROUTERS_INIT,
83};
84
85static void call_script(const int, const char *const *, void *);
86static size_t dname_labeldec(char *, size_t, const char *);
87static int safefile(const char *);
88
89#define	_ARGS_OTHER	otherconf_script, ifi->ifname
90#define	_ARGS_RESADD	resolvconf_script, "-a", ifi->ifname
91#define	_ARGS_RESDEL	resolvconf_script, "-d", ifi->ifname
92
93#define	CALL_SCRIPT(name, sm_head)					\
94	do {								\
95		const char *const sarg[] = { _ARGS_##name, NULL };	\
96		call_script(sizeof(sarg), sarg, sm_head);		\
97	} while(0)
98
99#define	ELM_MALLOC(p,error_action)					\
100	do {								\
101		p = malloc(sizeof(*p));					\
102		if (p == NULL) {					\
103			warnmsg(LOG_ERR, __func__, "malloc failed: %s", \
104				strerror(errno));			\
105			error_action;					\
106		}							\
107		memset(p, 0, sizeof(*p));				\
108	} while(0)
109
110int
111sockopen(void)
112{
113	static u_char *rcvcmsgbuf = NULL, *sndcmsgbuf = NULL;
114	int sndcmsglen, on;
115	static u_char answer[1500];
116	struct icmp6_filter filt;
117
118	sndcmsglen = rcvcmsglen = CMSG_SPACE(sizeof(struct in6_pktinfo)) +
119	    CMSG_SPACE(sizeof(int));
120	if (rcvcmsgbuf == NULL && (rcvcmsgbuf = malloc(rcvcmsglen)) == NULL) {
121		warnmsg(LOG_ERR, __func__,
122		    "malloc for receive msghdr failed");
123		return (-1);
124	}
125	if (sndcmsgbuf == NULL && (sndcmsgbuf = malloc(sndcmsglen)) == NULL) {
126		warnmsg(LOG_ERR, __func__,
127		    "malloc for send msghdr failed");
128		return (-1);
129	}
130	if ((rssock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6)) < 0) {
131		warnmsg(LOG_ERR, __func__, "socket: %s", strerror(errno));
132		return (-1);
133	}
134
135	/* specify to tell receiving interface */
136	on = 1;
137	if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVPKTINFO, &on,
138	    sizeof(on)) < 0) {
139		warnmsg(LOG_ERR, __func__, "IPV6_RECVPKTINFO: %s",
140		    strerror(errno));
141		exit(1);
142	}
143
144	/* specify to tell value of hoplimit field of received IP6 hdr */
145	on = 1;
146	if (setsockopt(rssock, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, &on,
147	    sizeof(on)) < 0) {
148		warnmsg(LOG_ERR, __func__, "IPV6_RECVHOPLIMIT: %s",
149		    strerror(errno));
150		exit(1);
151	}
152
153	/* specfiy to accept only router advertisements on the socket */
154	ICMP6_FILTER_SETBLOCKALL(&filt);
155	ICMP6_FILTER_SETPASS(ND_ROUTER_ADVERT, &filt);
156	if (setsockopt(rssock, IPPROTO_ICMPV6, ICMP6_FILTER, &filt,
157	    sizeof(filt)) == -1) {
158		warnmsg(LOG_ERR, __func__, "setsockopt(ICMP6_FILTER): %s",
159		    strerror(errno));
160		return(-1);
161	}
162
163	/* initialize msghdr for receiving packets */
164	rcviov[0].iov_base = (caddr_t)answer;
165	rcviov[0].iov_len = sizeof(answer);
166	rcvmhdr.msg_name = (caddr_t)&from;
167	rcvmhdr.msg_iov = rcviov;
168	rcvmhdr.msg_iovlen = 1;
169	rcvmhdr.msg_control = (caddr_t) rcvcmsgbuf;
170
171	/* initialize msghdr for sending packets */
172	sndmhdr.msg_namelen = sizeof(struct sockaddr_in6);
173	sndmhdr.msg_iov = sndiov;
174	sndmhdr.msg_iovlen = 1;
175	sndmhdr.msg_control = (caddr_t)sndcmsgbuf;
176	sndmhdr.msg_controllen = sndcmsglen;
177
178	return (rssock);
179}
180
181void
182sendpacket(struct ifinfo *ifi)
183{
184	struct in6_pktinfo *pi;
185	struct cmsghdr *cm;
186	int hoplimit = 255;
187	ssize_t i;
188	struct sockaddr_in6 dst;
189
190	dst = sin6_allrouters;
191	dst.sin6_scope_id = ifi->linkid;
192
193	sndmhdr.msg_name = (caddr_t)&dst;
194	sndmhdr.msg_iov[0].iov_base = (caddr_t)ifi->rs_data;
195	sndmhdr.msg_iov[0].iov_len = ifi->rs_datalen;
196
197	cm = CMSG_FIRSTHDR(&sndmhdr);
198	/* specify the outgoing interface */
199	cm->cmsg_level = IPPROTO_IPV6;
200	cm->cmsg_type = IPV6_PKTINFO;
201	cm->cmsg_len = CMSG_LEN(sizeof(struct in6_pktinfo));
202	pi = (struct in6_pktinfo *)CMSG_DATA(cm);
203	memset(&pi->ipi6_addr, 0, sizeof(pi->ipi6_addr));	/*XXX*/
204	pi->ipi6_ifindex = ifi->sdl->sdl_index;
205
206	/* specify the hop limit of the packet */
207	cm = CMSG_NXTHDR(&sndmhdr, cm);
208	cm->cmsg_level = IPPROTO_IPV6;
209	cm->cmsg_type = IPV6_HOPLIMIT;
210	cm->cmsg_len = CMSG_LEN(sizeof(int));
211	memcpy(CMSG_DATA(cm), &hoplimit, sizeof(int));
212
213	warnmsg(LOG_DEBUG, __func__,
214	    "send RS on %s, whose state is %d",
215	    ifi->ifname, ifi->state);
216	i = sendmsg(rssock, &sndmhdr, 0);
217	if (i < 0 || (size_t)i != ifi->rs_datalen) {
218		/*
219		 * ENETDOWN is not so serious, especially when using several
220		 * network cards on a mobile node. We ignore it.
221		 */
222		if (errno != ENETDOWN || dflag > 0)
223			warnmsg(LOG_ERR, __func__, "sendmsg on %s: %s",
224			    ifi->ifname, strerror(errno));
225	}
226
227	/* update counter */
228	ifi->probes++;
229}
230
231void
232rtsol_input(int s)
233{
234	u_char ntopbuf[INET6_ADDRSTRLEN], ifnamebuf[IFNAMSIZ];
235	int l, ifindex = 0, *hlimp = NULL;
236	ssize_t msglen;
237	struct in6_pktinfo *pi = NULL;
238	struct ifinfo *ifi = NULL;
239	struct ra_opt *rao = NULL;
240	struct icmp6_hdr *icp;
241	struct nd_router_advert *nd_ra;
242	struct cmsghdr *cm;
243	char *raoptp;
244	char *p;
245	struct in6_addr *addr;
246	struct nd_opt_hdr *ndo;
247	struct nd_opt_rdnss *rdnss;
248	struct nd_opt_dnssl *dnssl;
249	size_t len;
250	char nsbuf[INET6_ADDRSTRLEN + 1 + IFNAMSIZ + 1];
251	char dname[NI_MAXHOST];
252	struct timeval now;
253	struct timeval lifetime;
254
255	/* get message.  namelen and controllen must always be initialized. */
256	rcvmhdr.msg_namelen = sizeof(from);
257	rcvmhdr.msg_controllen = rcvcmsglen;
258	if ((msglen = recvmsg(s, &rcvmhdr, 0)) < 0) {
259		warnmsg(LOG_ERR, __func__, "recvmsg: %s", strerror(errno));
260		return;
261	}
262
263	/* extract optional information via Advanced API */
264	for (cm = (struct cmsghdr *)CMSG_FIRSTHDR(&rcvmhdr); cm;
265	    cm = (struct cmsghdr *)CMSG_NXTHDR(&rcvmhdr, cm)) {
266		if (cm->cmsg_level == IPPROTO_IPV6 &&
267		    cm->cmsg_type == IPV6_PKTINFO &&
268		    cm->cmsg_len == CMSG_LEN(sizeof(struct in6_pktinfo))) {
269			pi = (struct in6_pktinfo *)(CMSG_DATA(cm));
270			ifindex = pi->ipi6_ifindex;
271		}
272		if (cm->cmsg_level == IPPROTO_IPV6 &&
273		    cm->cmsg_type == IPV6_HOPLIMIT &&
274		    cm->cmsg_len == CMSG_LEN(sizeof(int)))
275			hlimp = (int *)CMSG_DATA(cm);
276	}
277
278	if (ifindex == 0) {
279		warnmsg(LOG_ERR, __func__,
280		    "failed to get receiving interface");
281		return;
282	}
283	if (hlimp == NULL) {
284		warnmsg(LOG_ERR, __func__,
285		    "failed to get receiving hop limit");
286		return;
287	}
288
289	if ((size_t)msglen < sizeof(struct nd_router_advert)) {
290		warnmsg(LOG_INFO, __func__,
291		    "packet size(%zd) is too short", msglen);
292		return;
293	}
294
295	icp = (struct icmp6_hdr *)rcvmhdr.msg_iov[0].iov_base;
296
297	if (icp->icmp6_type != ND_ROUTER_ADVERT) {
298		/*
299		 * this should not happen because we configured a filter
300		 * that only passes RAs on the receiving socket.
301		 */
302		warnmsg(LOG_ERR, __func__,
303		    "invalid icmp type(%d) from %s on %s", icp->icmp6_type,
304		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
305		    INET6_ADDRSTRLEN),
306		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
307		return;
308	}
309
310	if (icp->icmp6_code != 0) {
311		warnmsg(LOG_INFO, __func__,
312		    "invalid icmp code(%d) from %s on %s", icp->icmp6_code,
313		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
314		    INET6_ADDRSTRLEN),
315		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
316		return;
317	}
318
319	if (*hlimp != 255) {
320		warnmsg(LOG_INFO, __func__,
321		    "invalid RA with hop limit(%d) from %s on %s",
322		    *hlimp,
323		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
324		    INET6_ADDRSTRLEN),
325		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
326		return;
327	}
328
329	if (pi && !IN6_IS_ADDR_LINKLOCAL(&from.sin6_addr)) {
330		warnmsg(LOG_INFO, __func__,
331		    "invalid RA with non link-local source from %s on %s",
332		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
333		    INET6_ADDRSTRLEN),
334		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
335		return;
336	}
337
338	/* xxx: more validation? */
339
340	if ((ifi = find_ifinfo(pi->ipi6_ifindex)) == NULL) {
341		warnmsg(LOG_INFO, __func__,
342		    "received RA from %s on an unexpected IF(%s)",
343		    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf,
344		    INET6_ADDRSTRLEN),
345		    if_indextoname(pi->ipi6_ifindex, ifnamebuf));
346		return;
347	}
348
349	warnmsg(LOG_DEBUG, __func__,
350	    "received RA from %s on %s, state is %d",
351	    inet_ntop(AF_INET6, &from.sin6_addr, ntopbuf, INET6_ADDRSTRLEN),
352	    ifi->ifname, ifi->state);
353
354	nd_ra = (struct nd_router_advert *)icp;
355
356	/*
357	 * Process the "O bit."
358	 * If the value of OtherConfigFlag changes from FALSE to TRUE, the
359	 * host should invoke the stateful autoconfiguration protocol,
360	 * requesting information.
361	 * [RFC 2462 Section 5.5.3]
362	 */
363	if (((nd_ra->nd_ra_flags_reserved) & ND_RA_FLAG_OTHER) &&
364	    !ifi->otherconfig) {
365		warnmsg(LOG_DEBUG, __func__,
366		    "OtherConfigFlag on %s is turned on", ifi->ifname);
367		ifi->otherconfig = 1;
368		CALL_SCRIPT(OTHER, NULL);
369	}
370
371	/* Initialize ra_opt per-interface structure. */
372	gettimeofday(&now, NULL);
373	if (!TAILQ_EMPTY(&ifi->ifi_ra_opt))
374		while ((rao = TAILQ_FIRST(&ifi->ifi_ra_opt)) != NULL) {
375			if (rao->rao_msg != NULL)
376				free(rao->rao_msg);
377			TAILQ_REMOVE(&ifi->ifi_ra_opt, rao, rao_next);
378			free(rao);
379		}
380	else
381		TAILQ_INIT(&ifi->ifi_ra_opt);
382
383#define	RA_OPT_NEXT_HDR(x)	(struct nd_opt_hdr *)((char *)x + \
384				(((struct nd_opt_hdr *)x)->nd_opt_len * 8))
385
386	/* Process RA options. */
387	warnmsg(LOG_DEBUG, __func__, "Processing RA");
388	raoptp = (char *)icp + sizeof(struct nd_router_advert);
389	while (raoptp < (char *)icp + msglen) {
390		ndo = (struct nd_opt_hdr *)raoptp;
391		warnmsg(LOG_DEBUG, __func__, "ndo = %p", raoptp);
392		warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_type = %d",
393		    ndo->nd_opt_type);
394		warnmsg(LOG_DEBUG, __func__, "ndo->nd_opt_len = %d",
395		    ndo->nd_opt_len);
396
397		switch (ndo->nd_opt_type) {
398		case ND_OPT_RDNSS:
399			rdnss = (struct nd_opt_rdnss *)raoptp;
400
401			/* Optlen sanity check (Section 5.3.1 in RFC 6106) */
402			if (rdnss->nd_opt_rdnss_len < 3) {
403				warnmsg(LOG_INFO, __func__,
404		    			"too short RDNSS option"
405					"in RA from %s was ignored.",
406					inet_ntop(AF_INET6, &from.sin6_addr,
407						  ntopbuf, INET6_ADDRSTRLEN));
408				break;
409			}
410
411			addr = (struct in6_addr *)(raoptp + sizeof(*rdnss));
412			while ((char *)addr < (char *)RA_OPT_NEXT_HDR(raoptp)) {
413				if (inet_ntop(AF_INET6, addr, ntopbuf,
414				    INET6_ADDRSTRLEN) == NULL) {
415					warnmsg(LOG_INFO, __func__,
416		    			    "an invalid address in RDNSS option"
417					    " in RA from %s was ignored.",
418					    inet_ntop(AF_INET6, &from.sin6_addr,
419					    ntopbuf, INET6_ADDRSTRLEN));
420					addr++;
421					continue;
422				}
423				if (IN6_IS_ADDR_LINKLOCAL(addr))
424					/* XXX: % has to be escaped here */
425					l = snprintf(nsbuf, sizeof(nsbuf),
426					    "%s%c%s", ntopbuf,
427					    SCOPE_DELIMITER,
428					    ifi->ifname);
429				else
430					l = snprintf(nsbuf, sizeof(nsbuf),
431					    "%s", ntopbuf);
432				if (l < 0 || (size_t)l >= sizeof(nsbuf)) {
433					warnmsg(LOG_ERR, __func__,
434					    "address copying error in "
435					    "RDNSS option: %d.", l);
436					addr++;
437					continue;
438				}
439				warnmsg(LOG_DEBUG, __func__, "nsbuf = %s",
440				    nsbuf);
441
442				ELM_MALLOC(rao, break);
443				rao->rao_type = ndo->nd_opt_type;
444				rao->rao_len = strlen(nsbuf);
445				rao->rao_msg = strdup(nsbuf);
446				if (rao->rao_msg == NULL) {
447					warnmsg(LOG_ERR, __func__,
448					    "strdup failed: %s",
449					    strerror(errno));
450					free(rao);
451					addr++;
452					continue;
453				}
454				/* Set expiration timer */
455				memset(&rao->rao_expire, 0, sizeof(rao->rao_expire));
456				memset(&lifetime, 0, sizeof(lifetime));
457				lifetime.tv_sec = ntohl(rdnss->nd_opt_rdnss_lifetime);
458				timeradd(&now, &lifetime, &rao->rao_expire);
459
460				TAILQ_INSERT_TAIL(&ifi->ifi_ra_opt, rao, rao_next);
461				addr++;
462			}
463			break;
464		case ND_OPT_DNSSL:
465			dnssl = (struct nd_opt_dnssl *)raoptp;
466
467			/* Optlen sanity check (Section 5.3.1 in RFC 6106) */
468			if (dnssl->nd_opt_dnssl_len < 2) {
469				warnmsg(LOG_INFO, __func__,
470		    			"too short DNSSL option"
471					"in RA from %s was ignored.",
472					inet_ntop(AF_INET6, &from.sin6_addr,
473						  ntopbuf, INET6_ADDRSTRLEN));
474				break;
475			}
476
477			/*
478			 * Ensure NUL-termination in DNSSL in case of
479			 * malformed field.
480			 */
481			p = (char *)RA_OPT_NEXT_HDR(raoptp);
482			*(p - 1) = '\0';
483
484			p = raoptp + sizeof(*dnssl);
485			while (1 < (len = dname_labeldec(dname, sizeof(dname),
486			    p))) {
487				/* length == 1 means empty string */
488				warnmsg(LOG_DEBUG, __func__, "dname = %s",
489				    dname);
490
491				ELM_MALLOC(rao, break);
492				rao->rao_type = ndo->nd_opt_type;
493				rao->rao_len = strlen(dname);
494				rao->rao_msg = strdup(dname);
495				if (rao->rao_msg == NULL) {
496					warnmsg(LOG_ERR, __func__,
497					    "strdup failed: %s",
498					    strerror(errno));
499					free(rao);
500					break;
501				}
502				/* Set expiration timer */
503				memset(&rao->rao_expire, 0, sizeof(rao->rao_expire));
504				memset(&lifetime, 0, sizeof(lifetime));
505				lifetime.tv_sec = ntohl(dnssl->nd_opt_dnssl_lifetime);
506				timeradd(&now, &lifetime, &rao->rao_expire);
507
508				TAILQ_INSERT_TAIL(&ifi->ifi_ra_opt, rao, rao_next);
509				p += len;
510			}
511			break;
512		default:
513			/* nothing to do for other options */
514			break;
515		}
516		raoptp = (char *)RA_OPT_NEXT_HDR(raoptp);
517	}
518	ra_opt_handler(ifi);
519	ifi->racnt++;
520
521	switch (ifi->state) {
522	case IFS_IDLE:		/* should be ignored */
523	case IFS_DELAY:		/* right? */
524		break;
525	case IFS_PROBE:
526		ifi->state = IFS_IDLE;
527		ifi->probes = 0;
528		rtsol_timer_update(ifi);
529		break;
530	}
531}
532
533static char resstr_ns_prefix[] = "nameserver ";
534static char resstr_sh_prefix[] = "search ";
535static char resstr_nl[] = "\n";
536static char resstr_sp[] = " ";
537
538int
539ra_opt_handler(struct ifinfo *ifi)
540{
541	struct ra_opt *rao;
542	struct script_msg *smp1, *smp2, *smp3;
543	struct timeval now;
544	TAILQ_HEAD(, script_msg) sm_rdnss_head =
545		TAILQ_HEAD_INITIALIZER(sm_rdnss_head);
546	TAILQ_HEAD(, script_msg) sm_dnssl_head =
547		TAILQ_HEAD_INITIALIZER(sm_dnssl_head);
548	int dcount, dlen;
549
550	dcount = 0;
551	dlen = strlen(resstr_sh_prefix) + strlen(resstr_nl);
552	gettimeofday(&now, NULL);
553	TAILQ_FOREACH(rao, &ifi->ifi_ra_opt, rao_next) {
554		switch (rao->rao_type) {
555		case ND_OPT_RDNSS:
556			if (timercmp(&now, &rao->rao_expire, >)) {
557				warnmsg(LOG_INFO, __func__,
558					"expired rdnss entry: %s",
559					(char *)rao->rao_msg);
560				break;
561			}
562			ELM_MALLOC(smp1, continue);
563			ELM_MALLOC(smp2, goto free1);
564			ELM_MALLOC(smp3, goto free2);
565			smp1->sm_msg = resstr_ns_prefix;
566			TAILQ_INSERT_TAIL(&sm_rdnss_head, smp1, sm_next);
567			smp2->sm_msg = rao->rao_msg;
568			TAILQ_INSERT_TAIL(&sm_rdnss_head, smp2, sm_next);
569			smp3->sm_msg = resstr_nl;
570			TAILQ_INSERT_TAIL(&sm_rdnss_head, smp3, sm_next);
571
572			break;
573		case ND_OPT_DNSSL:
574			if (timercmp(&now, &rao->rao_expire, >)) {
575				warnmsg(LOG_INFO, __func__,
576					"expired dnssl entry: %s",
577					(char *)rao->rao_msg);
578				break;
579			}
580			dcount++;
581			/* Check resolv.conf(5) restrictions. */
582			if (dcount > 6) {
583				warnmsg(LOG_INFO, __func__,
584				    "dnssl entry exceeding maximum count (%d>6)"
585				    ": %s", dcount, (char *)rao->rao_msg);
586				break;
587			}
588			if (256 < dlen + strlen(rao->rao_msg) +
589			    strlen(resstr_sp)) {
590				warnmsg(LOG_INFO, __func__,
591				    "dnssl entry exceeding maximum length "
592				    "(>256): %s", (char *)rao->rao_msg);
593				break;
594			}
595			ELM_MALLOC(smp1, continue);
596			ELM_MALLOC(smp2, goto free1);
597			if (TAILQ_EMPTY(&sm_dnssl_head)) {
598				ELM_MALLOC(smp3, goto free2);
599				smp3->sm_msg = resstr_sh_prefix;
600				TAILQ_INSERT_TAIL(&sm_dnssl_head, smp3,
601				    sm_next);
602			}
603			smp1->sm_msg = rao->rao_msg;
604			TAILQ_INSERT_TAIL(&sm_dnssl_head, smp1, sm_next);
605			smp2->sm_msg = resstr_sp;
606			TAILQ_INSERT_TAIL(&sm_dnssl_head, smp2, sm_next);
607			dlen += strlen(rao->rao_msg) + strlen(resstr_sp);
608			break;
609		default:
610			break;
611		}
612		continue;
613free2:
614		free(smp2);
615free1:
616		free(smp1);
617	}
618	/* Add \n for DNSSL list. */
619	if (!TAILQ_EMPTY(&sm_dnssl_head)) {
620		ELM_MALLOC(smp1, goto ra_opt_handler_freeit);
621		smp1->sm_msg = resstr_nl;
622		TAILQ_INSERT_TAIL(&sm_dnssl_head, smp1, sm_next);
623	}
624	TAILQ_CONCAT(&sm_rdnss_head, &sm_dnssl_head, sm_next);
625
626	if (!TAILQ_EMPTY(&sm_rdnss_head))
627		CALL_SCRIPT(RESADD, &sm_rdnss_head);
628	else
629		CALL_SCRIPT(RESDEL, NULL);
630
631ra_opt_handler_freeit:
632	/* Clear script message queue. */
633	if (!TAILQ_EMPTY(&sm_rdnss_head)) {
634		while ((smp1 = TAILQ_FIRST(&sm_rdnss_head)) != NULL) {
635			TAILQ_REMOVE(&sm_rdnss_head, smp1, sm_next);
636			free(smp1);
637		}
638	}
639	return (0);
640}
641
642static void
643call_script(const int argc, const char *const argv[], void *head)
644{
645	const char *scriptpath;
646	int fd[2];
647	int error;
648	pid_t pid, wpid;
649	TAILQ_HEAD(, script_msg) *sm_head;
650
651	if ((scriptpath = argv[0]) == NULL)
652		return;
653
654	fd[0] = fd[1] = -1;
655	sm_head = head;
656	if (sm_head != NULL && !TAILQ_EMPTY(sm_head)) {
657		error = pipe(fd);
658		if (error) {
659			warnmsg(LOG_ERR, __func__,
660			    "failed to create a pipe: %s", strerror(errno));
661			return;
662		}
663	}
664
665	/* launch the script */
666	pid = fork();
667	if (pid < 0) {
668		warnmsg(LOG_ERR, __func__,
669		    "failed to fork: %s", strerror(errno));
670		return;
671	} else if (pid) {	/* parent */
672		int wstatus;
673
674		if (fd[0] != -1) {	/* Send message to the child if any. */
675			ssize_t len;
676			struct script_msg *smp;
677
678			close(fd[0]);
679			TAILQ_FOREACH(smp, sm_head, sm_next) {
680				len = strlen(smp->sm_msg);
681				warnmsg(LOG_DEBUG, __func__,
682				    "write to child = %s(%zd)",
683				    smp->sm_msg, len);
684				if (write(fd[1], smp->sm_msg, len) != len) {
685					warnmsg(LOG_ERR, __func__,
686					    "write to child failed: %s",
687					    strerror(errno));
688					break;
689				}
690			}
691			close(fd[1]);
692		}
693		do {
694			wpid = wait(&wstatus);
695		} while (wpid != pid && wpid > 0);
696
697		if (wpid < 0)
698			warnmsg(LOG_ERR, __func__,
699			    "wait: %s", strerror(errno));
700		else
701			warnmsg(LOG_DEBUG, __func__,
702			    "script \"%s\" terminated", scriptpath);
703	} else {		/* child */
704		int nullfd;
705		char **_argv;
706
707		if (safefile(scriptpath)) {
708			warnmsg(LOG_ERR, __func__,
709			    "script \"%s\" cannot be executed safely",
710			    scriptpath);
711			exit(1);
712		}
713		nullfd = open("/dev/null", O_RDWR);
714		if (nullfd < 0) {
715			warnmsg(LOG_ERR, __func__,
716			    "open /dev/null: %s", strerror(errno));
717			exit(1);
718		}
719		if (fd[0] != -1) {	/* Receive message from STDIN if any. */
720			close(fd[1]);
721			if (fd[0] != STDIN_FILENO) {
722				/* Connect a pipe read-end to child's STDIN. */
723				if (dup2(fd[0], STDIN_FILENO) != STDIN_FILENO) {
724					warnmsg(LOG_ERR, __func__,
725					    "dup2 STDIN: %s", strerror(errno));
726					exit(1);
727				}
728				close(fd[0]);
729			}
730		} else
731			dup2(nullfd, STDIN_FILENO);
732
733		dup2(nullfd, STDOUT_FILENO);
734		dup2(nullfd, STDERR_FILENO);
735		if (nullfd > STDERR_FILENO)
736			close(nullfd);
737
738		_argv = malloc(sizeof(*_argv) * argc);
739		if (_argv == NULL) {
740			warnmsg(LOG_ERR, __func__,
741				"malloc: %s", strerror(errno));
742			exit(1);
743		}
744		memcpy(_argv, argv, (size_t)argc);
745		execv(scriptpath, (char *const *)_argv);
746		warnmsg(LOG_ERR, __func__, "child: exec failed: %s",
747		    strerror(errno));
748		exit(1);
749	}
750
751	return;
752}
753
754static int
755safefile(const char *path)
756{
757	struct stat s;
758	uid_t myuid;
759
760	/* no setuid */
761	if (getuid() != geteuid()) {
762		warnmsg(LOG_NOTICE, __func__,
763		    "setuid'ed execution not allowed\n");
764		return (-1);
765	}
766
767	if (lstat(path, &s) != 0) {
768		warnmsg(LOG_NOTICE, __func__, "lstat failed: %s",
769		    strerror(errno));
770		return (-1);
771	}
772
773	/* the file must be owned by the running uid */
774	myuid = getuid();
775	if (s.st_uid != myuid) {
776		warnmsg(LOG_NOTICE, __func__,
777		    "%s has invalid owner uid\n", path);
778		return (-1);
779	}
780
781	switch (s.st_mode & S_IFMT) {
782	case S_IFREG:
783		break;
784	default:
785		warnmsg(LOG_NOTICE, __func__,
786		    "%s is an invalid file type 0x%o\n",
787		    path, (s.st_mode & S_IFMT));
788		return (-1);
789	}
790
791	return (0);
792}
793
794/* Decode domain name label encoding in RFC 1035 Section 3.1 */
795static size_t
796dname_labeldec(char *dst, size_t dlen, const char *src)
797{
798	size_t len;
799	const char *src_origin;
800	const char *src_last;
801	const char *dst_origin;
802
803	src_origin = src;
804	src_last = strchr(src, '\0');
805	dst_origin = dst;
806	memset(dst, '\0', dlen);
807	while (src && (len = (uint8_t)(*src++) & 0x3f) &&
808	    (src + len) <= src_last) {
809		if (dst != dst_origin)
810			*dst++ = '.';
811		warnmsg(LOG_DEBUG, __func__, "labellen = %zd", len);
812		memcpy(dst, src, len);
813		src += len;
814		dst += len;
815	}
816	*dst = '\0';
817
818	/*
819	 * XXX validate that domain name only contains valid characters
820	 * for two reasons: 1) correctness, 2) we do not want to pass
821	 * possible malicious, unescaped characters like `` to a script
822	 * or program that could be exploited that way.
823	 */
824
825	return (src - src_origin);
826}
827